The explosion happened on 116th Street and Park Avenue just after 9:30 a.m. One of the buildings had a piano repair shop with apartments on top, while the other building housed a church, the report said.

The explosion was a result of a gas leak, NYC Mayor Bill de Blasio said in a press conference this afternoon.

The only indication of danger, he said, came 15 minutes prior to the explosion when a resident in a nearby building called Con Edison, reporting the smell of gas. ConEd dispatched workers but the collapse happened before they could get there, officials said.

"This is a tragedy of the worst kind because there was no indication in time to save people," de Blasio said.

Two women were killed, and at least 54 others were injured, authorities told CBS. There are also a "number of missing individuals," the mayor said. Authorities will conduct a search through the rubble as soon as the fire is put out, he said.

Video from the scene showed smoke bellowing out of the area and firefighters dousing the area with water from ladders. There were 250 firefighters on the scene.

Metro-North trains in the area are suspended as a result of debris on the tracks. Subway trains are running as scheduled and are honoring Metro-North tickets.